Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, VA 23173, United States.
J Colloid Interface Sci. 2010 Dec 1;352(1):50-8. doi: 10.1016/j.jcis.2010.08.043. Epub 2010 Aug 19.
Thermodynamic and adsorption properties of protein monolayer electrochemistry (PME) are examined for Pseudomonas aeruginosa azurin (AZ) immobilized at an electrode modified with a networked film of monolayer-protected clusters (MPCs) to assess if nanoparticle films of this nature offer a more homogeneous adsorption interface compared to traditional self-assembled monolayer (SAM) modified electrodes. Specifically, electrochemistry is used to assess properties of surface coverage, formal potential, peak broadening, and electron transfer (ET) kinetics as a function of film thickness. The modification of a surface with dithiol-linked films of MPCs (Au(225)C6(75)) provides a more uniform binding interface for AZ that results in voltammetry with less peak broadening (<110mV) compared to SAMs (>120-130mV). Improved homogeneity of the MPC interface for protein adsorption is confirmed by atomic force microscopy imaging that shows uniform coverage of the gold substrate topography and by electrochemical analysis of film properties during systematic desorption of AZ, which indicates a more homogeneous population of adsorbed protein at MPC films. These results suggest MPC film assemblies may be used in PME to provide greater molecular level control of the protein adsorption interface, a development with applications for strategies to study biological ET processes as well as the advancement of biosensor technologies.
蛋白质单层电化学（PME）的热力学和吸附性质在电极上进行了研究，该电极经过修饰，形成了单层保护簇（MPC）的网络薄膜，其中固定了铜绿假单胞菌菌蓝（AZ），以评估此类纳米粒子薄膜是否比传统的自组装单层（SAM）修饰电极提供了更均匀的吸附界面。具体来说，电化学用于评估表面覆盖率、形式电位、峰展宽和电子转移（ET）动力学等性质，作为薄膜厚度的函数。用二硫键连接的 MPC（Au(225)C6(75)）薄膜修饰表面为 AZ 提供了更均匀的结合界面，导致伏安法峰展宽较小（<110mV），而 SAMs 则较大（>120-130mV）。原子力显微镜成像证实了 MPC 界面在蛋白质吸附方面的均匀性，显示了金基底形貌的均匀覆盖，以及在 AZ 系统解吸过程中对薄膜性质的电化学分析，这些都表明 MPC 薄膜中吸附的蛋白质具有更均匀的种群。这些结果表明，MPC 薄膜组件可用于 PME 中，以提供对蛋白质吸附界面更大的分子水平控制，这一发展在研究生物 ET 过程的策略以及生物传感器技术的发展方面具有应用前景。
